1. Field of the Invention
The present invention relates to an automatic spray painting machine comprising a first movable portion movable in a direction toward and away from a work object, a second movable portion movable in a specified direction perpendicular to the moving direction of the first movable portion, and a spray nozzle supported by a supporting portion through the first and second movable portions.
2. Description of the Prior Art
In the conventional automatic spray painting machines of the above noted type, an actuator for one of the first and second movable portions which is positioned closer to the supporting portion in the supporting order is mounted on the supporting portion, while an actuator for the other movable portion which is positioned closer to the spray nozzle in the supporting order is mounted on the aforementioned movable portion mounted on the supporting portion.
In order to oscillate the spray nozzle in the moving direction of the second movable portion for varying its direction, a third actuator for oscillating the spray nozzle is mounted on the movable portion of the two movable portions which is positioned closer to the spray nozzle in the supporting order. (see Japanese Utility Model Application "Kokai" No. 63-201667.)
Each movable portion in the conventional machines is moved in considerably high speed, e.g. 10-80 m/min. However, the actuators are mounted on these movable portions movable in high speed, which results in heavy weight of the movable portions to excessively increase inertia in movement of the movable portions. Thus, large clatters occur when the movable portions move in reverse directions. This causes an uneven painted condition and deterioration of the durability of the machine. In addition, rigid and reinforced components are required for the actuators and devices in the movable portions carrying the actuators, which results in high manufacturing cost of the whole machine.
An object of the present invention is to provide an improved automatic spray painting machine which solves the above noted problems of the conventional art.